Ah, quantum immortality. I really don't think that infamous thought experiment is of any particular usefulness to physics as it doesn't give any conceivably testable predictions. It seems instead as simply wishful thinking, by assuming a many worlds interpretation of quantum mechanics. But physics doesn't care about interpretations. It cares about the results of experiments.

This is how I see the experiment: The spin-state measuring apparatus ticks each time it measures a proton with spin up, and activates a lethal weapon when it measures a spin down. The experiment begins and the apparatus ticks until it doesn't, at which point the subject dies. And it's as simple as that. He/she isn't part of some everlasting/branching quantum mechanical system. The probability wave function is in the protons, not the entire apparatus. The apparatus is what measures and thus collapses the wave function.

If one chooses to believe in MW interpretation or that wave functions somehow encompasses the whole system so as to be relevant to the perceptions of reality of the subject (kind of a stretch because that's really not what a wave function means), and further that consciousness itself somehow makes the jump to other universes, then that's cool, feel free to try the experiment and see what happens. But it's not useful unless it's both valid and you find a way to report your results back to us.

The holographic universe idea is an interesting one, too. I'm not very familiar with it though.

It's kind of a twisted version of Pascal's Bet on the existence of God, but applied to an as-yet-to-be-created all powerful AI that reaches back to punish anyone who didn't help it manifest. Hahaha. So you'd better help the AI be born, or face eternity in a kind of artificial hell.